Sofa



FIG. 1 is a top and front perspective view of a sofa showing my new design;

FIG. 2 is a top and front perspective view thereof from a higher angle than in FIG. 1;

FIG. 3 is a side elevational view thereof from the left of FIG. 1, the side elevational view from the right of FIG. 1 being the mirror image thereof; and,

FIG. 4 is a rear elevational view thereof. 

The ornamental design for a sofa, as shown and described. 